(CNN) - A bipartisan group of Senate negotiators is expected to announce Thursday it has reached an agreement designed to bolster border security mandates in the pending immigration reform bill, according to a Senate source involved in the negotiations.

The agreement includes a “border surge” plan, which would double the size of the border patrol from its current level of 21,000 agents and ensure that there would be 700 miles of fence, sources tell CNN.

A Senate aide familiar with the negotiations cautions there could be a last-minute change, but this is what is expected to be announced.FULL POST

Washington (CNN) - The Senate narrowly rejected a Republican-sponsored measure Thursday that would have bypassed the Obama administration's current objections to the Keystone XL pipeline and allowed construction on the controversial project to move forward immediately.

Fifty-six senators voted in favor of the amendment - four short of the 60 required for approval.

Washington (CNN) - A day after she shocked her colleagues and constituents by announcing her retirement, moderate Republican Sen. Olympia Snowe of Maine explained her decision and defended tough criticism she leveled at her colleagues when she announced why she would leave the Senate.

"People are just stunned by the debilitating partisanship, polarization and the overall dysfunction of the institution and political paralysis as we come, you know, to the point of extreme when it comes to resolving the problems facing our country," a frustrated Snowe told CNN Wednesday. "It's become an all or nothing proposition and that failure has eroded the public's confidence about the direction of this country and about governing institutions to be at the front lines of solving these problems."FULL POST